Differential effects of insecticides on mitochondrial membrane fluidity and ATPase activity between the wolf spider and the rice stem borer

Differential effects of methamidophos and three pyrethroids on ATPase activity and membrane fluidity of mitochondria were investigated between the wolf spider(Pirata subpiraticus(Boes.et Str.))and the rice stem borer(Chilo suppressalis(Walker)).Based on a comparison of LD_(50) values,the toxicities of the tested insecticides were higher to the wolf spider than to the rice stem borer.Cyhalothrin at 1×10~(–4) mmol L~(–1) caused inhibition of the mitochondrial Na~+-K~+-ATPase and Ca~(2+)-Mg~(2+)-ATPase activities,and it’s inhibitions on Na+-K+-ATPase and Ca~(2+)-Mg~(2+)-ATPase activities were significantly higher in the wolf spider(44 and 28%)than in the rice stem borer(19 and 11%).Methamidophos at 1×10~(–4) mmol L~(–1) decreased Ca~(2+)-Mg~(2+)-ATPase activity by 16 and 27%in the wolf spider and the rice stem borer,respectively,but no significant effect on the specific activity of Na+-K+-ATPase was observed.The DPH(1,6-diphenyl-1,3,5-hexatriene)fluorescence polarization values of mitochondrial membranes were not significantly affected by methamidophos in either species.However,cyhalothrin and alpha-cypermethrin induced the values of DPH polarization of mitochondrial membrane increasing with the concentration of cyhalothrin and alpha-cypermethrin from 20 to 100μmol L~(–1) in the rice stem borer and the wolf spider.Effect of ethofenprox on fluidity of the wolf spider and the rice stem borer was contrary.These results suggest that both inhibition of membrane ATPase and changes of membrane fluidity could be appended to the action mechanisms of pyrethroid insecticides.     

Deltamethrin resistance in the sea louse Caligus rogercresseyi (Boxhall and Bravo) in Chile: bioassay results and usage data for antiparasitic agents with references to Norwegian conditions

The sea louse Caligus rogercresseyi is a major threat to Chilean salmonid farming. Pyrethroids have been used for anticaligus treatments since 2007, but have shown reduced effect, most likely due to resistance development. Pyrethroid resistance is also a known problem in Lepeophtheirus salmonis in the Northern Hemisphere. This study describes the development of deltamethrin resistance in C. rogercresseyi based on bioassays and usage data for pyrethroids in Chilean aquaculture. These results were compared to bioassays from L. salmonis from Norway and to Norwegian usage data. Available deltamethrin bioassay results from 2007 and 2008, as well as bioassays from Norway, were collected and remodelled. Bioassays were performed on field‐collected sea lice in region X in Chile in 2012 and 2013. Bioassays from 2007 were performed prior to the introduction of pyrethroids to the Chilean market. Both the results from 2008 and 2012 showed an increased resistance. Increased pyrethroid resistance was also indicated by the increased use of pyrethroids in Chilean aquaculture compared with the production of salmonids. A similar trend was seen in the Norwegian usage data. The bioassay results from Chile from 2012 and 2013 also indicated a difference in the susceptibility to deltamethrin between male and female caligus.     

Are we analysing knockdown in the right way? how independence of the knockdown-recovery process from mortality may affect measures for behavioural effects in pesticide bioassays

In pesticide bioassays, especially those with neurotoxic agents, effects on animals are typically grouped into classes according to behaviour, such as normal and affected behaviour, which may range from unstable walking behaviour, to unable to move, to mortality. Generally, recovery is observed in all these effect classes, except the last. Mortality, however, disturbs the analysis of the recovery processes because it decreases the number of animals that otherwise could have shown a reversible effect. We consider that this interaction between mortality and other, reversible, effects is a conceptual problem, and give arguments in favour of analysing changes in behaviour and mortality as two independent, simultaneously occurring neurotoxic syndromes. As an illustration, two data sets are analysed in both ways and these show that marked differences may exist between conclusions reached by the two viewpoints. The consequences thereof are discussed in relation to toxico-kinetic explanations for neurotoxicant effects on behaviour and mortality. © 1999 Society of Chemical Industry     

Miticidal pyrethroids having an isobutyranilidoxime ether skeleton

Isobutyranilidoxime meta-phenoxybenzyl ethers and related compounds were synthesized. Their insecticidal activities measured against Periplaneta americana by injection were lower than that of phenothrin by factors of at least 1/60. However, some compounds were comparable to or only slightly less potent than phenothrin and tetramethrin in miticidal activity tested by a contact method against Dermatophagoides farinae, D. pteronyssinus and Tyrophagus putrescentiae. © 1998 SCI     

Synthetic pyrethroids containing a C–C triple bond

The three commercial synthetic pyrethroids containing a carbon–carbon triple bond, α-ethynyl-2-methylpent-2-enyl (1R)-trans-chrysanthemate, (S)-2-methyl-4-oxo-3-(2-propynyl)cyclopent-2-enyl (1R)-trans,cis-chrysanthemate and [2,5-dioxo-3-(2-propynyl)-1-imidazolidinyl]methyl (1R)-trans-chrysanthemate are reviewed with emphasis on their inventive histories. Their chemistry and efficacy are described briefly. The relationship between stereochemistry and the biological activity is also discussed. © 1998 SCI.     

不同抗性水平家蝇对有机磷、拟除虫菊酯等药剂的交互抗性研究

报道对辛硫磷和溴氰菊酯具有不同抗性水平的家蝇对有机磷、拟除虫菊酯及其他药剂的交互抗性情况和生化机制。处于高抗（R／S为625）和极高抗（R／S为547276）水平的抗溴氰菊酯家蝇、以及处于中抗（R／S为21．89）和高抗（R／S为310．72）水平的抗辛硫磷家蝇,对DDT及拟除虫菊酯类药剂均表现出明显的交互抗性;处于高抗和极高抗的抗溴氰菊酯家蝇以及处于中抗的抗干硫磷家蝇,对灭多威、abamectin及有机磷类药剂均不表现交互抗性;但处于高抗的抗辛硫磷家蝇则对有机磷类药剂表现出中等水平的交互抗性,对灭多威和abamectin无交互抗性。离休酶系分析结果表明,不同抗性水平家蝇的交互抗性情况不同,这与家蝇体内酯酶、多功能氧化酶、谷胱甘肽-S-转移酶和乙酸胆碱酯酶的酶活或特性存在差异有关。     

分散液液微萃取-高效液相色谱法测定枸杞中拟除虫菊酯类农药残留的研究

目的 本研究建立了分散液液微萃取-高效液相色谱法测定枸杞中溴氰菊酯和氰戊菊酯农药残留的检测方法。方法 对萃取剂与分散剂的种类、萃取剂与分散剂的体积比、pH值、离子强度、萃取时间等影响因素进行了考察。结果 研究结果表明,以甲醇为分散剂,三氯甲烷为萃取剂,萃取剂与分散剂的体积比为1:4,pH=7,萃取时间3 min,NaCl含量为2％时对枸杞中溴氰菊酯和氰戊菊酯萃取效果最佳。色谱检测方法为：Hypersil ODS2色谱柱(4.6 mm×250 mm,5 μm)；流动相为乙腈-水梯度洗脱；紫外检测波长230 nm；流速为1.0 mL/min。结论 氰戊菊酯和溴氰菊酯分别在0.13-26μg/mL(r=0.9992)和0.17-34μg/mL(r=0.9998)浓度范围内线性关系良好,相对标准偏差为5.25-5.80%,检出限为0.05 μg/mL。